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On the instantaneous shrinking of the support of solution to the Cauchy problem for an anisotropic parabolic equation. (Russian, English) Zbl 1224.35187

Ukr. Mat. Zh. 61, No. 5, 625-640 (2009); translation in Ukr. Math. J. 61, No. 5, 747-763 (2009).
The instantaneous compactification phenomenon is the one where a solution \(u(x,t)\), \(x\in \mathbb R^N\), \(0\leq t\leq T\), of a Cauchy problem has a compact support for any \(t>0\), though the initial function is nonzero on the whole space \(\mathbb R^N\). The author finds conditions for the instantaneous compactification for the equation \[ \frac{\partial}{\partial t}\left(| u| ^{\beta -1}u\right)-\sum\limits_{i=1}^N \frac{\partial}{\partial x_i}\left(| \frac{\partial u}{\partial x_i}| ^{p_i-2} \frac{\partial u}{\partial x_i}\right)+| u| ^{\lambda -1}u=0 \] where \(\beta >0\), \(p_i>1+\beta\) (\(i=1,\dots ,N\)), \(0<\lambda <\beta\). Earlier this problem was studied for the isotropic case (\(p_1=p_2=\cdots =p_N\)); see, for example, S. P. Degtyarev [Sb. Math. 199, No. 4, 511–538 (2008); translation from Mat. Sb. 199, No. 4, 37–64 (2008; Zbl 1172.35036)].

MSC:

35K55 Nonlinear parabolic equations

Citations:

Zbl 1172.35036
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